Timeline for Examples of complexes of modules for wich homomorphisms "homological" implies "homotopic"
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Dec 9, 2012 at 23:19 | comment | added | Fernando Muro | Over $\mathbb Z$ it is very easy, take two abelian groups $A$ and $B$ with non-vanishing $\operatorname{Ext}^1(A,B)$. This abelian group classifies homotopy classes $A\rightarrow B[1]$, and all these maps obviously induce the trivial morphism in homology by dimension reasons. I took this as being "non research level". | |
| Dec 9, 2012 at 18:02 | comment | added | Neil Epstein | Well, it would be nice to see an example of a pair of complexes over a non-vnr ring (e.g. over Z) and a pair of maps between them that are homologous but not homotopic. | |
| Dec 25, 2011 at 20:56 | comment | added | Fernando Muro | Don't you find simple enough what I've said? | |
| Dec 22, 2011 at 19:36 | comment | added | One_math_boy | Sorry, but can you give some simple examples? | |
| Dec 21, 2011 at 23:46 | history | edited | Fernando Muro | CC BY-SA 3.0 |
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| Dec 21, 2011 at 22:59 | history | answered | Fernando Muro | CC BY-SA 3.0 |